Abstract
An attempt to extend passive dynamic walking from a slope to a horizontal surface have begun since the late 80's about the same time as the research on passive dynamic walking. A method using inclination of an upper body has been originally examined by McGeer, which enables a biped with the upper body to walk on the horizontal surface using counter torque of the torque generating to maintain the body inclination. However there are no deep insight into properties of the method such as stability against the inclination and robustness. Moreover, no researchers could achieve a real biped using the body inclination, and then the method would be sensitive against uncertainties (e.g., the ground undulation and small obstacles), accordingly. In this paper, we introduce an upper body and circular arc feet to a compass model biped and achieve various dynamic walking gait using thrust via the upper body inclination through numerical simulations. Stability of the walking gait is also analyzed using the Poincaré method. Moreover, a geometric tracking control using a cyclic motion of the biped walking is introduced in order to achieve more robust gait. Stability of the controlled walking is also analyzed using a Poincaré map of HZD. In addition, we discuss the difference between the walking using the upper body inclination and the geometric tracking controlled walking.
